This invention relates generally to static VAR generators and it relates in particular to a timing generator for a control circuit for a static VAR generator.
Static VAR generators may be provided for utilization with AC loads which are highly reactive to provide generally balanced currents at the input terminals of the power source. A control circuit is usually necessary with the static VAR generator. It would be advantageous to utilize the concept of a phase comparator or detector in combination with a low pass filter and a voltage controlled oscillator to provide timing output signals which may be utilized in the control system for the VAR generator. U.S. Pat. No. 3,534,285 entitled "Digital Phase Control Circuit for Synchronizing an Oscillator to a Harmonic Or a Reference Frequency" by P. J. Kobold et al issued Oct. 13, 1970 teaches a system where a signal is applied to a phase detector which in turn controls the voltage controlled oscillator that provides a signal which is applied to a counter thus providing a binary output signal. A second output of the counter is applied through a feedback loop to the phase detector to insure that the VCO functions in a stable manner. U.S. Pat. No. 3,495,184 entitled "Phase Locked Loop Having Improved Acquisition Range" by F. A. Perkins, Jr. et al issued Feb. 10, 1970 and U.S. Pat. No. 3,363,194 entitled "Phase Lock Loop With Extended Capture Range" by R. E. Hileman teach the utilization of a phase detector applying a signal to a low pass filter and then to a voltage controlled oscillator. None of the previous references disclose a timing generator utilizing a dual mode amplifier/filter and a ripple cancelling phase detector for controlling the phase angle of the SCR's utilized in the compensating network of a static VAR generator. It would be advantageous if such control were so provided.